Detcon DM-100 - Manual (Page 25)

Model DM-100
DM-100 Instruction Manual Rev. 3.3 Page 21 of 40
4.2 Replacement of ITM
1. Remove the power source to the sensor assembly. Disconnect all sensor wire connections at the
Junction Box Terminal Board taking note of the wire connections.
NOTE
It is necessary to remove power to the Junction box while changing the ITM in order to
maintain area classification.
2. Use a wrench and the wrench flats provided at the top section of the ITM and unthread the ITM until it
can be removed.
3. Use a
1
/
8
" Allen wrench to release the locking cap head screw that locks the ITM and Splash Guard
Adapter together (One turn will suffice - Do not remove setscrew completely).
4. Unthread and remove the Splash Guard Adapter and Splash Guard from the ITM. These will be re-
used with the new ITM.
5. Gently remove the plug-in toxic gas sensor from the old ITM and install it in the new ITM. Orient the
plug-in sensors so that it matches the female connector pins on the new ITM and press the sensor in
firmly to make proper connection.
6. Thread the Splash Guard Adapter onto the new ITM until snug, tighten the locking cap head screw and
reinstall Splash Guard.
7. Feed the sensor assembly wires through the 3 /
4
" female NPT mounting hole and thread the assembly
into the J-box until tight and the ITM faces toward the front access point. Use the locking nut to secure
the ITM in this position. Connect the sensor assembly wires to the terminal board inside the Junction
Box (Section 2.6).
8. Check and/or perform Zero Calibration and Span Calibration (Section 3.3, Calibration).
4.3 Replacement of the Model 100 Terminal Board
1. Remove the power source to the sensor assembly.
NOTE
It is necessary to remove power to the Junction Box while changing the Model 100
Terminal Board in order to maintain area classification.
2. Remove the junction box cover and remove the Loop Powered Display, if one is installed.
3. Remove the power connector on the terminal board.
4. Unplug all other connectors from the terminal board, noting where they are plugged into.
5. Remove the four 6-32 screws holding the terminal board to the base of the junction box and remove
the terminal board.
6. Install the new terminal board using the four 6-32 screws removed in Step 5.
7. If the unit has the DM-100 Display Terminal Board, ensure that the jumper on the terminal board is set
properly (Section 2.6.1, DM-100 Display Terminal Board Settings).
8. Re-connect the sensor connector to the terminal board and all other connections removed in Step 4.